Personal computing device having single-cell battery

ABSTRACT

The present invention features a personal computing device that may be powered by a single battery having a single lithium-ion cell or by a plurality of lithium-ion cells connected in parallel. The personal computing device may provide computing power comparable to that of conventional laptop computers and execute an operating system and application software comparable to that executed by conventional laptop computers. Furthermore, the battery&#39;s time between charging, when used to power the personal computing device, may be similar to the time between charging of a multi-cell battery when used to power a conventional laptop computer.

BACKGROUND

[0001] 1. Field of the Invention

[0002] The present invention relates to computing devices and, moreparticularly, to power sources for personal computers.

[0003] 1. Related Art

[0004] There is an increasing need for computer systems that arepowerful, mobile, and inexpensive. Although mobile computing devices(such as laptop computers and personal digital assistants (PDAs)) andother mobile electronic devices (such as cellular telephones) aretypically capable of receiving power either from an electrical outlet orfrom one or more batteries coupled to and contained within the housingof the device, the advantage of using outlet power is that it providespower for an essentially unlimited period of time. The primarydisadvantage of using outlet power is that it ties the computing deviceto being used within the vicinity of an available outlet and therebylimits the mobility of the device. The advantage of using battery poweris that it enables the device to be fully mobile while being used. Onedisadvantage of using battery power is that an individual battery canonly provide power for a limited period of time (such as a few hours).Once a battery runs out of power, the battery must be recharged byconnecting the device (or a separate charging station) to an outletpower source, often for several hours, to fully recharge the battery.

[0005] One strategy that users often adopt in response to the limitedpower capabilities of batteries is to travel with several fully-chargedbatteries, thereby enabling a discharged battery to be immediatelyreplaced with a fully-charged battery without the need to engage inbattery charging. Disadvantages of this strategy include the increasedcost of additional batteries and the increased burden of traveling withseveral batteries, thereby effectively decreasing the overall ease ofmobility of the mobile computing device.

[0006] Larger computing devices, particular those (such as laptopcomputers) that include power-hungry components such as hard diskdrives, optical media drives, and color display monitors, typically havesignificantly higher power requirements than smaller computing devicessuch as PDAs and tablet computers. Larger computing devices thereforetypically require relatively large and heavy batteries, therebyincreasing the overall size and weight of the computing device andincreasing the burden of traveling with such a device.

[0007] Although this problem may be mitigated by decreasing the size ofthe battery, doing so would result in a battery that discharges morequickly, possibly to an extent that users would find unacceptable. Forthese and other reasons, the tradeoff between battery size and batterypower storage capacity is a persistent feature of mobile computingdevice design.

[0008] What is needed, therefore, are techniques for enabling theimplementation of powerful mobile computing devices that are capable ofrunning on battery power for substantial periods of time.

SUMMARY

[0009] The present invention features a personal computing device thatmay be powered by a single battery having a single lithium-ion cell.Alternatively, the personal computing device may be powered by aplurality of lithium-ion cells connected in parallel. The personalcomputing device may provide computing power comparable to that ofconventional laptop computers and execute an operating system andapplication software comparable to that executed by conventional laptopcomputers. Furthermore, the battery's time between charging, when usedto power the personal computing device, may be similar to the timebetween charging of a multi-cell battery when used to power aconventional laptop computer.

[0010] Other features and advantages of various aspects and embodimentsof the present invention will become apparent from the followingdescription and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1A is a block diagram of the functional modules included in aconventional personal computing system;

[0012]FIG. 1B is a block diagram of the physical modules contained in aconventional personal computing system;

[0013]FIG. 2 is a block diagram of a personal computing device accordingto one embodiment of the present invention; and

[0014]FIG. 3A is a front view of a single-cell battery for use with thepersonal computing device of FIG. 2 according to one embodiment of thepresent invention; and

[0015]FIG. 3B is a side view of the single-cell battery of FIG. 3A.

DETAILED DESCRIPTION

[0016] The present invention features a personal computing device thatmay be powered by a single battery having a single lithium-ion cell.Alternatively, the personal computing device may be powered by aplurality of lithium-ion cells connected in parallel. The personalcomputing device may provide computing power comparable to that ofconventional laptop computers and execute an operating system andapplication software comparable to that executed by conventional laptopcomputers. Furthermore, the battery's time between charging, when usedto power the personal computing device, may be similar to the timebetween charging of a multi-cell battery when used to power aconventional laptop computer.

[0017] Most conventional computing systems are composed of subsystems,also referred to herein as “functional modules” or simply as “modules.”For example, a conventional computing system may include one or more ofeach of the following subsystems: (1) an information processingsubsystem (which may include, for example, a central processing unit(CPU)), (2) a power input and distribution subsystem (which may include,for example, a power supply and power bus), (3) a user input subsystem(which may include, for example, a conventional mouse and/or keyboard),(4) a user output subsystem (which may include, for example, aconventional monitor and/or printer), (5) a mass media storage andaccess subsystem (which may include, for example, a conventional harddisk drive), and (6) a network or inter-device communication subsystem(which may include, for example, a conventional network interface card(NIC) or a serial or parallel cable). The relationship of functionalmodules to physical components in computer systems is described in moredetail in the commonly-owned U.s. patent application Ser. No.10/173,734, entitled “Modular Computing System,” filed on Jun. 18, 2002,hereby incorporated by reference.

[0018] As used herein, the term “functional module” refers to a set ofhardware and/or software in a computing system that performs aparticular function. The terms “subsystem” and “module” are usedsynonymously with “functional module” herein. For example, a displaymodule in a conventional desktop computer may include the computer'sCPU, graphics card, video memory, monitor, and portions of the operatingsystem that process display information. Examples of other modulesinclude processing modules, input modules, and power modules. Afunctional module may be embodied in hardware, software, data and/orinstruction streams, and any combination thereof. A single physicaldevice in a computer system may be part of more than one functionalmodule.

[0019] As used herein, the term “computer” refers to a system thatincludes an information processing module, a power module, a user inputmodule, a user output module, and a storage module. These modules areinterconnected to form a unified system that is powered by the powermodule, receives user input using the user input module, processes theuser input (and other information) using the processing module, providesuser output using the user output module, and stores user input (andother information) using the storage module. Examples of computersinclude conventional desktop computers and laptop computers.

[0020] As used herein, the term “appliance” refers to a device thatincludes a power module, a user input module, and a user output module,but that lacks components that provide some or all of the functionalityof a conventional computer processing module and/or storage module. Anappliance therefore may rely at least in part on a connection to anetwork system or removable media to provide the missing functionalityof the processing and/or media storage modules. The modules in anappliance are interconnected to form a unified system that is powered bythe power module, receives user input using the user input module,processes the user input (and other information) using the (at leastpartially external) processing module, provides user output using theuser output module, and stores user input (and other information) usingthe (at least partially external) storage module. Examples of appliancesinclude personal digital assistants, cellular telephones, and web pads.

[0021] As used herein, the term “computing system” refers to bothcomputers and appliances. A computing system includes an input module,an output module, a power module, a processing module, and a storagemodule. A computing system may also include other modules, such as aninterdevice communication module.

[0022] Referring to FIG. 1A, one well-known implementation of a modularcomputing system is the conventional desktop computer 100 a, shown inblock diagram form. The desktop computer 100 a includes a processingmodule 102, a networking module 104, an input module 106, an outputmodule 108, a storage module 110, and a power module 112.

[0023] As used herein, the term “input module” refers to any functionalmodule (subsystem) that provides input to a computing system. Inputmodules may include devices such as keyboards, mice, styluses,trackballs, touch location devices such as touchpads and touch screens,microphones, scanners, cameras and video capture devices, wirelessreceivers, buttons, and switches. Input may, for example, be obtained bythe input module as the result of actions performed by a user (such astyping on a keyboard). Input may, however, be obtained without useractivity. For example, a network interface card may receive input over anetwork from another computer performing automated actions, and adigital camera may be configured to periodically capture images andprovide them as input to a computing system without further interactionfrom the user.

[0024] As used herein, the term “output module” refers to any functionalmodule (subsystem) that provides output to a user, to another module, orto another computing device. Output modules may include, for example,devices such as display monitors, speakers, printers, projectors, andwireless transmitters.

[0025] As used herein, the term “processing module” refers to anyfunctional module (subsystem) that processes information. Processingmodules may include one or more kinds of processor in any combination,such as a central processing unit (CPU), graphics processing unit, mathco-processing unit, or a digital signal processor.

[0026] As used herein, the term “storage module” refers to anyfunctional module (subsystem) that stores digital information. Storagemodules may include devices such as RAM, ROM, hard disk drives, floppydisk drives, optical drives (such as CD-ROM, CD-R, CD-RW, DVD-RAM, orDVD-ROM drives), or tape drives.

[0027] As used herein, the term “interdevice communication module”refers to any functional module (subsystem) that enables a component tocommunicate with another component. Typically, each component that is tocommunicate with another component contains its own interdevicecommunication module. Interdevice communication modules may enablecommunication over any kind of connection, such as serial cables,parallel cables, USB cables, or wireless connections. Interdevicecommunication modules may include devices such as serial controllers,parallel controllers, and network interface cards (NICs).

[0028] Referring again to FIG. 1A, the entire processing module 102, theentire networking module 104, and most or all of the media storagemodule are typically embodied in components contained within a singlephysical housing. Although such housings have various form factors, someof which (such as the “tower” model) are designed to rest on a floorrather than a desk, all such form factors fall within the desktopcomputer paradigm as described herein. For purposes of explanation, anysuch housing and the devices contained within it are referred to hereinas the “desktop component” of a desktop computer.

[0029] For example, referring to FIG. 1B, the physical components of atypical desktop computer 100 b are shown. The desktop computer 100 bincludes a desktop component 122, a keyboard 126 a, a mouse 126 b, amonitor 128 a, and a printer 128 b. The processing module 102 of thedesktop computer 100 b is embodied in a central processing unit (CPU)and related components within the desktop component 122. Similarly, thenetworking module 104 of the desktop computer 100 b is embodied in anetwork interface card (NIC) and related components within the desktopcomponent 122, and the power module 112 of the desktop computer 100 b isembodied in a power supply, transformer, and related components withinthe desktop component 122. The input module 106 of the desktop computer100 b consists of a keyboard 126 a, a mouse 126 b, and relatedcomponents within the desktop component 122. The output module 108 ofthe desktop computer 100 b consists of a monitor 128 a, a printer 128 b,and related components within the desktop component 122. The storagemodule 110 of the desktop computer 100 b consists of a hard disk drive(not shown) within the desktop component 122, an external opticalstorage device 130, and related components within the desktop component122. The “related components” described above typically include devicedrivers and other hardware and software for communicating with andcontrolling the keyboard 126a, mouse 126 b, monitor 128 a, printer 128b, and optical storage device 130, which are typically referred to as“peripheral devices.”

[0030] Conventional desktop components typically communicate withperipheral devices (such as the keyboard 126 a and the printer 128 b)via data ports, wireless streams, or physical connectors having variousbandwidths and form factors and employing various protocols. Suchperipheral devices are generally powered either independently by powermodules unique to each device, or draw power parasitically from thedesktop component 122.

[0031] In portable (mobile) computing systems, such as laptop computers,a single device often encapsulates a set of components that embody userinput modules (e.g., keyboard, trackpad, touchpad, buttons, levers,touchscreen, stylus, operating system, etc.), user output modules (e.g.,monitor, speakers, LEDs, vibration, etc.), processing modules (e.g.,CPU, memory, video processor, decoder), media storage modules (e.g.,hard disk drive, flash memory, smart card, ROM), and power modules(e.g., batteries, transformers, super capacitors, solar cells, springs).Encapsulation of input, output, and power modules within a single deviceis a common way in which portable computing systems address the need forportability. In addition to this encapsulation of multiple functionalmodules within a single device, portable computing systems often alsoinclude peripheral devices that provide the functionality of networkmodules (e.g., modems), inter-device communication modules (e.g., portreplicators, expansion cards), user input modules (e.g., mice,keyboards, microphones), user output modules (e.g., printers, externalspeakers), and power modules (e.g., external batteries and chargers).

[0032] Laptop computers, handheld computers, and personal digitalassistants (PDAs) are examples of such portable computing systems.Devices such as MP3 players, calculators, and handheld voice recordersare also portable computing systems with processing, input, output,power, and media modules specifically scaled and tailored to these nichedevices. Among portable computing systems are also specialized “mediareaders” such as digital phones, pagers, digital cameras, tape players,CD players, wireless email devices, portable DVD-players, mini-discplayers, and portable game players, which read a stream of media to theuser, either from a wireless source or from a removable media source.These readers, like appliances, may have some or all of their processingor media storage modules abstracted over a network or removable device.

[0033] Referring to FIG. 2, a block diagram is shown illustrating thearchitecture of a personal computing device 200 according to oneembodiment of the present invention. The personal computing device 200may include all of the functional modules of a computer as that term isdefined herein. For example, the personal computing device 200 includesa processor 202 a, such as the Crusoe 0.13 micron 128-bit TM5800processor from Transmeta Corporation of Santa Clara, Calif.; a randomaccess memory (RAM) 202 b, such as 8×256 Mbit DDR SDRAM available fromNanya Technology Corp. of Linkou, Taiwan; and a read-only memory 202 c(ROM). The processor 202 a transfers data to and from the RAM 202 b andROM 202 c over a system bus 202 d. A system bus controller 202 econtrols the flow of data between the system bus 202 d and aninput/output (I/O) bus 214, such as the M1535+Southbridge from AcerLaboratories, Inc. of San Jose, Calif. The processor 202 a, RAM 202 b,ROM 202 c, system bus 202 d, and system bus controller 202 e areexamples of components that implement a processing module.

[0034] The processor 202 a may be a processor, such as the Crusoeprocessor mentioned above, suitable for use in a conventional laptop ordesktop computer, and not typically found in appliances. Furthermore,the RAM 202 b may be RAM (such as DDR SDRAM) that is suitable for use ina conventional laptop or desktop computer and not typically found inappliances.

[0035] The personal computing device 200 also includes a networkingdevice 204 a for enabling the personal computing device 200 tocommunicate with other devices. A networking controller 204 b controlsthe flow of data between the networking device 204 a and the I/O bus214. For example, the networking controller 204 b may be an 802.11bwireless controller, such as the AT76C505 controller from AtmelCorporation of San Jose, Calif. Alternatively, the networking controller204 b may, for example, be a Bluetooth (IEEE 1394) controller, such asthe ZC2001 controller from Zeevo, Inc. of Santa Clara, Calif.

[0036] The networking device 204 a and networking controller 204 e areexamples of components that implement a networking module. Although thenetworking device 204 a is illustrated as external to the personalcomputing device 200 in FIG. 2, the networking device 204 aalternatively may be contained within the personal computing device 200.The term “networking” is used broadly herein to refer to any interdevicecommunication, and therefore encompasses not only communicationperformed according to “networking” protocols such as TCP/IP or 802.11b,but also to communication performed using direct device-to-devicecommunications means, such as serial, parallel, and SCSI cables.

[0037] The personal computing device 200 may, for example, include oneor more FireWire connectors for engaging in high-speed networking withother FireWire-enabled devices. FireWire is defined by IEEE Standard1394b, draft 1.0, dated Feb. 25, 2000, hereby incorporated by reference.In addition, the personal computing device 200 may include one or moreconventional computer buses such as a serial Peripheral ComponentInterconnect (PCI) bus and/or an Industry Standard Architecture (ISA)bus.

[0038] The personal computing device 200 also includes an input device206 a for enabling the personal computing device 200 to receive inputfrom users. An input controller 206 b controls the flow of data from theinput device 206 a to the I/O bus 214. The input device 206 a and inputcontroller 206 b are examples of components that implement an inputmodule. Mice, keyboards, and trackpads are examples of input devices.

[0039] The personal computing device 200 also includes an output device208 a for enabling the personal computing device 200 to provide outputto users. In one embodiment, the output device 208 a is a 5-inchTransflective WVGA TFT LCD (800*480, 64 k color) active-matrixtransflective color display from Samsung Electronics, Ltd. of Hong Kong.An output controller 208 b controls the flow of data from the I/O bus214 to the output device 208 a. The output device 208 a and outputcontroller 208 b are examples of components that implement an outputmodule. Although the output device 208 a is illustrated as external tothe personal computing device 200 in FIG. 2, the output device 208 aalternatively may be contained within the personal computing device 200.Monitors and printers are examples of output devices.

[0040] The personal computing device 200 also includes a persistentstorage device 210 a for enabling the personal computing device 200 tostore data on a tangible medium. In one embodiment, the persistentstorage device 210 a is a model MK2003GAH hard disk drive from ToshibaAmerica Electronic Components, Inc. of Irvine, Calif. A persistentstorage controller 210 b controls the flow of data between thepersistent storage device 210 and the I/O bus 214. The persistentstorage device 210 a and persistent storage controller 210 b areexamples of components that implement a storage module. Hard diskdrives, optical drives (such as CD drives and DVD drives), floppy diskdrives, and tape drives are examples of persistent storage devices.

[0041] The personal computing device 200 may be enclosed in a smallhousing and be lightweight. For example, in one embodiment of thepresent invention, the housing of the personal computing device 200 is4.1″ (105 mm) wide by 2.9″(74 mm) long by 0.9″ (22 mm) high, and weighsless than 9 ounces (250 grams). The personal computing device 200 maytherefore be small and lightweight enough to be at least as portable asa conventional laptop computer.

[0042] The personal computing device 200 also includes a single-cellbattery 212 for providing power to the other components of the personalcomputing device 200. Although the connections between the battery 212and the remaining components of the personal computing device 200 arenot shown in FIG. 2 for ease of illustration, those of ordinary skill inthe art will appreciate how to implement such connections. Thesingle-cell battery 212 and associated circuitry are an example of apower module. Alternatively, the personal computing device may bepowered by a plurality of lithium-ion cells connected in parallel.

[0043] The personal computing device 200 may be small and lightweightenough to be at least as portable as a conventional laptop computer andprovide computing power comparable to that of conventional laptopcomputers. Conventional laptop computers, however, typically aredesigned for use with multi-cell lithium-ion batteries. Each suchbattery includes a plurality of lithium-ion cells connected in series.Multi-cell batteries have been necessary to power conventional laptopcomputers because of the relatively high power requirements of suchcomputers.

[0044] Smaller mobile electronic devices, such as personal digitalassistants (PDAs) and cellular telephones, are often designed for usewith single-cell lithium-ion batteries. It has been possible for suchdevices to use single-cell batteries because such devices typically havesignificantly lower power requirements than laptop computers. A PDA, forexample, typically has a much smaller display screen than a laptopcomputer and lacks a powerful central processor which consumes such adominant fraction of the power of laptop computers. Although PDAs andcell phones are capable of running on batteries that are smaller andless heavy than laptop batteries, this feature comes at the expense ofcomputing power. PDAs and cell phones, for example, typically are notcapable of executing full-scale desktop operating systems or full-scaledesktop software applications.

[0045] In contrast, the personal computing device 200 shown in FIG. 2may provide computing power comparable to that of conventional laptopcomputers and execute an operating system (such as the Microsoft®Windows® 2000 Professional operating system) and application software(such as the Microsoft® Office business application suite) comparable tothat executed by conventional personal (desktop and laptop) computers.Such operating systems are typically not found in appliances.Furthermore, the discharge time of the battery 212, when used to powerthe personal computing device 200, may be similar to the discharge timeof a multi-cell battery when used to power a conventional laptopcomputer. For example, when the personal computing device 200 isimplemented using the particular example components described above, thelife of the battery may be approximately 3-6 hours. In this sense, thepersonal computing device 200 is an example of a personal computer (PC).

[0046] In one embodiment of the present invention, for example, thesingle-cell battery 212 is a single-cell lithium-ion battery, such asthe VM4172140 single-cell battery, available from Valence Technology,Inc. of Austin, Tex. Referring to FIGS. 3A-3B, in this embodiment thebattery 212 has a width 302 of 72.0±0.5 mm, a length 304 of 140.0±0.5mm, and a maximum thickness 306 of 4.1 mm. Each of the terminals 308 a-bof the battery 212 has a width 310 of 12.5 mm, a height 312 of 20.0±50mm, and a negligible thickness. Each of the terminals 308 a-b is offsetfrom the edge of the battery 212 by a distance 314 of 11.2 mm, andcorresponding edges of the terminals 308 a-b are separate by a distance316 of 37.2 mm.

[0047] In this embodiment the battery 212 has a nominal operatingvoltage of 3.8 VDC and a capacity of 2750 mAh, with a constant C/2current to 4.2 Volt limit, then constant voltage (4.2V) with floatingcurrent taper to C/20, then discharge at C/5. The battery has an initialimpedance of 0.20 mOhm, measured at 30% SOC, 1 kHz AC. The batteryweighs 79 g and has an operating temperature range of −20 to +60° C.Unless otherwise stated, all values just stated are nominal and testconditions are at 23° C., C/2 charge rate and C/5 discharge rate.

[0048] In one embodiment of the present invention, for example, themaximum expected power consumption of the primary components of thepersonal computer device 200 are as shown in TABLE 1 Maximum PowerComponent Consumption (mW) Display (e.g., output device 208a) 300Display backlight 400 Graphics controller 477 Southbridge (e.g., I/O bus214) 250 Processor 202a 7500 Hard drive (e.g., storage device 1300 210a)802.11b wireless (e.g., networking 1304 device 204a) Bluetooth wireless(e.g., networking 100 device 204a) Clock generator 100 Audio CODEC 270Headphone amplifier 200 RAM 202b 877 USB power out 2500 Cooling fan 600

[0049] The sum of the values shown in Table 1 is approximately 16.2watts. The VM4172140 battery has a capacity of 15.8 Watt-hours. Theexpected life of the battery 212 under the conditions assumed for Table1, therefore, is approximately one hour. The values shown in Table 1,however, are maximum reasonable steady-state power consumption values.The rate during normal use will typically be several times lower thanthe total value of 16.2 watts, because all components of the personalcomputing device 200 seldom operate at their maximum consumption levelseither simultaneously or for long periods of time. Typical powerconsumption is expected to be on the order of 2.5-5W. As a result, thetypical battery life is expected to be in the range of 3-6 hours, basedon the particular components shown in Table 1.

[0050] Among the advantages of the invention are one or more of thefollowing. The use of a single-cell battery rather than a multiple-cellbattery may enable the personal computing device 200 to be smaller,lighter, and less expensive to manufacture than computing devices havingcomparable computing power.

[0051] In addition, the use of a single-cell battery or multiple cellsin parallel makes it possible to use particularly small DC-DCconverters, thereby enabling the personal computing device 200 to have aparticularly small size. The smallest DC-DC converters currentlyavailable include the VT103, VT201, VT202 and VT223 converters,available from Volterra Semiconductor Corporation of Fremont, Calif.Such converters cannot run from the higher voltages provided by twolithium cells in series. The use of a single lithium cell or multiplelithium-ion cells in parallel, therefore, advantageously enables the useof particularly small DC-DC converters.

[0052] Another advantage of embodiments of the present invention is thatthey may enable both step-up and step-down DC-DC power converters in thepersonal computing device 200 to operate more efficiently. As iswell-known to those of ordinary skill in the art, both step-up andstep-down DC-DC converters operate at higher efficiencies when theoutput voltage is closer to the input voltage. Therefore, providing anarchitecture which uses a low-voltage battery, such as the single-cellbattery 212, enables DC-DC converters in the personal computing device200 to operate more efficiently than in systems requiring higher-voltagepower sources.It is to be understood that although the invention hasbeen described above in terms of particular embodiments, the foregoingembodiments are provided as illustrative only, and do not limit ordefine the scope of the invention. Various other embodiments are alsowithin the scope of the claims. For example, elements and componentsdescribed herein may be further divided into additional components orjoined together to form fewer components for performing the samefunctions.

[0053] Although the personal computing device 200 is described above asexecuting the Microsoft® Windows® 2000 Professional operating system,this is not a limitation of the present invention. Rather, embodimentsof the present invention may be used in conjunction with other operatingsystems. For example, embodiments of the present invention may be usedin conjunction with any operating system that is compliant with theWin32 application program interface (API), such as Microsoft Windows®98, Microsoft Windows® ME, and Microsoft Windows NT®, and MicrosoftWindows XP.

[0054] Although one embodiment of the battery 212 described aboveutilizes Manganese cathode material, this is not a limitation of thepresent invention. Rather, other chemistries may be used, such as Cobaltor Phosphate materials. Furthermore, the particular dimensions and otherproperties of the battery 212 described herein are provided merely forpurposes of example and do not constitute limitations of the presentinvention.

[0055] What is claimed is:

1. A device comprising: a processing subsystem; an input subsystem; anoutput subsystem; a persistent storage subsystem; an interdevicecommunication subsystem comprising a serialized Peripheral ComponentInterconnect (PCI) bus; and a power subsystem comprising a single-cellbattery.
 2. The device of claim 1, wherein the single-cell batterycomprises a lithium-ion battery.
 3. The device of claim 1, wherein thepower subsystem comprises a plurality of single-cell batteries connectedin parallel.
 4. The device of claim 3, wherein the plurality ofsingle-cell batteries comprises a plurality of single-cell lithium-ionbatteries.
 5. The device of claim 1, wherein the processing subsystemcomprises a DDR SDRAM.
 6. The device of claim 1, wherein the interdevicecommunication subsystem further comprises a wireless communicationscontroller.
 7. The device of claim 6, wherein the wireless networkingcontroller comprises an 802.11b-compliant wireless communicationscontroller.
 8. The device of claim 6, wherein the wireless networkingcontroller comprises an IEEE 1394-compliant wireless communicationscontroller.
 9. The device of claim 1, wherein the processing subsystemcomprises a processor having a system bus that is at least 128 bitswide.
 10. The device of claim 1, further comprising an operating systemsuitable for execution on a desktop computer.
 11. A device comprising: aprocessing subsystem; an input subsystem; an output subsystem; apersistent storage subsystem; an interdevice communication subsystemcomprising a bus compliant with IEEE standard 1394; and a powersubsystem comprising a single-cell battery.
 12. The device of claim 11,wherein the single-cell battery comprises a lithium-ion battery.
 13. Thedevice of claim 11, wherein the power subsystem comprises a plurality ofsingle-cell batteries connected in parallel.
 14. The device of claim 13,wherein the plurality of single-cell batteries comprises a plurality ofsingle-cell lithium-ion batteries.
 15. The device of claim 11, whereinthe processing subsystem comprises a DDR SDRAM.
 16. The device of claim11, wherein the interdevice communication subsystem further comprises awireless communications controller.
 17. The device of claim 16, whereinthe wireless networking controller comprises an 802.11b-compliantwireless communications controller.
 18. A device comprising: aprocessing subsystem; an input subsystem; an output subsystem; apersistent storage subsystem; an interdevice communication subsystemcomprising an Industry Standard Architecture (ISA) bus; and a powersubsystem comprising a single-cell battery.
 19. The device of claim 18,wherein the single-cell battery comprises a lithium-ion battery.
 20. Thedevice of claim 18, wherein the power subsystem comprises a plurality ofsingle-cell batteries connected in parallel.
 21. The device of claim 20,wherein the plurality of single-cell batteries comprises a plurality ofsingle-cell lithium-ion batteries.
 22. The device of claim 18, whereinthe processing subsystem comprises a DDR SDRAM.
 23. A device comprising:a processing subsystem; an input subsystem; an output subsystem; apersistent storage subsystem; an interdevice communication subsystem; anoperating system suitable for execution on a desktop computer; and apower subsystem comprising a single-cell battery.
 24. The device ofclaim 23, wherein the single-cell battery comprises a lithium-ionbattery.
 25. The device of claim 23, wherein the power subsystemcomprises a plurality of single-cell batteries connected in parallel.26. The device of claim 25, wherein the plurality of single-cellbatteries comprises a plurality of single-cell lithium-ion batteries.27. The device of claim 23, wherein the processing subsystem comprises aDDR SDRAM.
 28. The device of claim 23, wherein the interdevicecommunication subsystem comprises a wireless communications controller.29. The device of claim 28, wherein the wireless networking controllercomprises an 802.11b-compliant wireless communications controller. 30.The device of claim 23, wherein the operating system comprises anoperating system compliant with the Win32 application program interface.31. A device comprising: a processing subsystem comprising a double datarate synchronous dynamic random access memory (DDR-SDRAM); an inputsubsystem; an output subsystem; a persistent storage subsystem; aninterdevice communication subsystem; and a power subsystem comprising asingle-cell battery.
 32. The device of claim 31, wherein the single-cellbattery comprises a lithium-ion battery.
 33. The device of claim 31,wherein the power subsystem comprises a plurality of single-cellbatteries connected in parallel.
 34. The device of claim 33, wherein theplurality of single-cell batteries comprises a plurality of single-celllithium-ion batteries.
 35. The device of claim 31, wherein theinterdevice communication subsystem comprises a wireless communicationscontroller.
 36. The device of claim 35, wherein the wireless networkingcontroller comprises an 802.11b-compliant wireless communicationscontroller.
 37. A device comprising: a processing subsystem comprising aprocessor having a system bus that is at least 128 bits wide; an inputsubsystem; an output subsystem; a persistent storage subsystem; and apower subsystem comprising a single-cell battery.
 38. The device ofclaim 37, wherein the single-cell battery comprises a lithium-ionbattery.
 39. The device of claim 37, wherein the power subsystemcomprises a plurality of single-cell batteries connected in parallel.40. The device of claim 39, wherein the plurality of single-cellbatteries comprises a plurality of single-cell lithium-ion batteries.41. The device of claim 37, wherein the processing subsystem comprises aDDR SDRAM.
 42. The device of claim 37, wherein the operating systemcomprises an operating system compliant with the Win32 applicationprogram interface.